Scripts - Dynamic text

Hi,

I have a file in which I have to replace the text with system date. The text needs to be changed on daily basis automatically.
Assume, in "test.txt", I have below lines:
LOAD FILE
MYFILE 'c:/test/test_2010_09_24.txt
-----
-----

In the above, MYFILE value changes every day, the next day it should be
MYFILE 'c:/test/test_2010_09_25.txt (i.e. the filename format is 'test_<yyyy>_<mm>_<dd>' from system date.

How can we do this by shell script?

Thanks in advance.

MYFILE="c:/test/test_$(date +%Y_%m_%d).txt"